1. Field of the Invention
The present invention relates to stable graft polymer dispersions of low viscosity at temperatures below 100.degree. C. More particularly, the invention relates to graft copolymer dispersions prepared by the improved process of in situ free radical polymerization of ethylenically unsaturated monomer or monomers in polyol in the presence of an effective amount of a preformed polymeric stabilizer.
2. Prior Art
The prior art, as evidenced by U.S. Pat. Nos. 3,652,659; 3,875,258; 3,950,317; and U.S. Pat. No. Re. 28,715 and No. Re. 29,014, teaches the preparation of graft copolymer dispersions which are useful in the preparation of polyurethanes by the free radical polymerization of ethylenically unsaturated monomers in the presence of polyols. These patents disclose various methods of preparing graft polymer dispersions. The prior art is silent regarding the desirability of using a preformed polymeric stabilizer based on alkoxylated styrene-allyl alcohol polymers during the addition of ethylenically unsaturated monomer or monomers.